Needle-bar guide apparatus for zigzag sewing machines



FUJI KOIKE April 1 7, 1962 5 SheetsSheet 1 Filed NOV. 13, 1959 ELWIYRRLUIE ATTORNEY April 17, 1962 3,029,761

NEEDLE-BAR GUIDE APPARATUS FOR ZIGZAG SEWING MACHINES FLIJJI KOIKE 3 Sheets-Sheet 2 Filed NOV. 13, 1959 INVENTOR /'M// Afl/A ATTORNEY 4 A ril 17, 1962 FUJI KOIKE 3,0 9, 6

NEEDLE-BAR GUIDE APPARATUS FOR ZIGZAG SEWING MACHINES Filed Nov. 13, 1959 5 Sheets-Sheet 5 Fig. 4

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INVENTOR ATTORNEY Fug-i Kozge 3,929,761 NEEDLE-BAR GUHDE APPARATUS FGR ZEGZAG SEG MACHINES Fuji Koike, Showa-ku, Nagoya, .lapan, assignor to Nikon Mishin Seize Kahushiki Keisha, Nagoya, Japan, a corporation of Japan Filed Nov. 13, 1359, Ser. No. 852,786 Claims priority, application Japan Nov. 15, 1953 2 Claims. (Cl. 112-158) This invention relates to a needle-bar guide apparatus for zigzag sewing machines and more particularly to improvements in the mechanism of a needle-bar guide designed to oscillate around a fixed axis.

The primary object of the present invention is to simplify the construction and assembly of those zigzag sewing machines in which the shuttle rotates or oscillates in a lateral direction, whereby the cost of manufacture is reduced and thus to popularize this type of zigzag sewing machines for use in the ordinary family.

Another object of the invention is to provide for obtaining beautiful stitches without skipping by insuring that the loop-taker seizes Without fail the loop of the needle-thread at the vicinity of the needle.

A still another object is to lessen the space occupied by the needle-bar guide apparatus within the hollow head of the sewing machine frame by minimizing the oscillating radius of the aforesaid needle-bar guide within the hollow head and moreover to enlarge sufficiently the oscillating radius of the needle point with respect to the material worked.

Other objects and features of the invention will be apparent from a consideration of the following detailed description taken with the accompanying drawings, which illustrate a zigzag lock-stitch sewing machine embodying this invention, wherein:

FIG. 1 is a perspective view of the mechanism of i the essential parts with the frame having been removed;

FIG. 2 is a front elev-ational view showing the mechanism of the essential parts with the face plate removed and the lower part of. the machine bed cut away;

FIG. 3 is an explanatory drawing showing the locus of the oscillatory movements of the needle in accordance with the arrangement of the present invention as compared with that of the conventional arrangement; and

FIGS. 4 and 5 are detailed views on an enlarged scale of the means for imparting and adjusting the amplitude of oscillation of the needle-bar guide, FIG. 5, being taken on lines X and Y in FIG. 4.

Referring more specifically to the drawings, 1 is the bed of the sewing machine; 2, the standard provided at one end of the aforesaid bed 1; 3, the bracket-arm extending from the aforesaid standard 2; 4, the hollow arm; 5, the cover plate covering the top part of the aforesaid bracket-arm 3, attached as to be freely removable; 6, the main shaft supported as to be rotatable in the aforesaid bracket-arm 3 with a crank plate 7 being secured to its one end and a hand wheel 8 to the other; and 9, the needle-thread take-up mechanism consisting of four crooks links coupled to the aforesaid crank plate 7 by means of an auxiliary crank 10. .1 1 is the needle bar to which lower end has been affixed a needle 12; 13, the needlebar link, which imparts the up-and-down reciprocatory movements to the aforesaid needle-bar 11, with one end being pivotally mounted to the aforesaid auxiliary crank 10 and the other to a needle-bar pin 14 secured to the aforesaid needle-bar 11 so as to permit said both ends to make a universal movement. 15 is a resser-bar in parallel to the needle-bar 11 and dis posed to the rear thereof to which lower end is secured a resser-foot 16. 17 is a pitman pivotally attached to 3,29,7tii Patented Apr, 17, 1962 the crank section 18 of the aforesaid main shaft 6 with its lower end being connected to a rock-shaft 19. The aforesaid rock-shaft 19 is coupled with a loop-taker shaft 20 and also to a driving-shaft 21 which imparts the upand down movements to a feed dog to be described hereinafter. 22 is the usual oscillating loop-taker, which being secured to the aforesaid loop-taker shaft 20, accomplishes oscillatory movements in connection with the up-and-down reciprocatory movement of the foregoing'needle-bar 11. 23 is a feed-advancing cam secured to the aforesaid main shaft 6, and 24 is a forked pitman with its one end having a forked section 25 embracing the afores-aid feed-advancing cam 23 and its other end connected to a rock-shaft 26 mounted underneath the aforesaid bed 1. 27 is the feed dog which is imparted by the aforesaid shafts 21 and 25 both upand-down as well as lateral movements in accordance with the up-and-down reciprocatory movements of the aforesaid needle 12, whereby the work is fed in the direction in which it is being sewn. 28 is an eccentric cam which rotates by means of gears 29 and 30. 31 is an oscillating piece provided with a groove 32 in the upper surface thereof, with its one end pivotally attached with a pivot 33 to a part of the aforesaid bracket-arm 3, and this oscillating piece 31 is capable of oscillating through a given amplitude centering around the aforesaid pivot 33 by means of the aforesaid eccentric cam 28. This oscillating movement is then transmitted to a needle-bar guide 42 to be described hereinafter through a needle-bar guide oscillating rod 36 which is coupled to a connecting member 35 having at its tip a block 34 pivoted thereto which block 34 fits in the aforesaid groove 32. 37 is the adjusting arm which one end is pivotally attached to a part of the aforesaid standard 2 with a screw 38. At one end of the aforesaid adjusting arm 37 a groove 40 is provided so as to embrace slidably a block 39 pivotally attached to the upper side of the tip of the aforesaid connecting member 35, with said block 39 being in the same axis as theaforesaid block 34. At the other end projecting to the outside of the aforesaid standard 2 there is provided a laterally movable manual adjusting lever 41 suitably coupled to a holding device. Accordingly, by operating the manual adjusting lever 41 laterally whereby the distance of the block 34 fitted in the groove 32 of the aforesaid oscillating piece 31 with respect to the axis 33 is changed, it becomes possible to regulate the needle-bar amplitude.

This invention relates to a zigzag lock-stitch sewing machine of, the construction as hereinabove described characterized by the provision of a needle-bar guide apparatus as will be described hereinafter. the drawings, 42 is a needle-bar guide supported with pivots 43 in the hollow arm 4 as to be rotatable around the axis of said pivots 43, and to the rocking side of this needle-bar guide is transfixed perpendicularly the aforesaid needle-bar 11. And the axis of the aforesaid pivots 43 is given an inclination such that it intersects the axis of the aforesaid needle-bar 11 at a point above the needle-bar. Furthermore, the aforesaid needle-bar guide 42 is coupled to the aforesaid needle-bar guide oscillating rod 36, whereby the former makes reciprocatory rotations around the axis of the aforesaid pivots 43.

Furthermore, in this invention the axis of the pivots 43 does not necessarily need to intersect with the axis of the needle-bar 11. Namely, in this invention, it sufiices to satisfy the conditions that the relative positions of the axis of the pivots 43 and the axis of the needle-bar 11 are in a non-parallel state, and moreover that at least at the needle-bar the aforesaid axes do not intersect, i.e., an extension of the pivotal axis of the needle-bar guide would pass outside the extremities of As shown in the needle-bar, and further that the lower they proceed the wider the spread becomes.

As described hereinabove, the object of this invention is ,to make possible the low-cost manufacture of a zigzag sewing machine so as to adapt it for family use.

Its object is particularly to manufacture at still lower costs a zigzag sewing machine of the type in which the shuttle rotates or oscillates in a fixed position while the needle alone is made to oscillate in a lateral direction. This type of zigzag machine not having a mechanism for oscillating the shuttle in a lateral direction can not only be manufactured at low cost but also is already widely known as having the characteristic that the appearance of its zigzag stitches excels that of those zigzag machines in which the shuttle is made to oscillate in a lateral direction together with the needle. And, inasmuch as in the conventional zigzag sewing machine of this type in practically all cases the mechanism for oscillating the needle-bar guide was of the vertical type, i.e., a combination of devices rotating or oscillating around a lateral axis, the aforesaid needle-bar guide was pivoted as to oscillate around a given axis at substantially right angle to a plane including the locus of the movement of the loop-takers loop-seizing beak.

However, on account of the fact that this mechanism for oscillating the needle-bar requires much trouble in its assembly and attachment, there is the defect that the cost becomes large. In order to overcome this by making the mechanism for oscillating the aforesaid needlebar into an easily assembled and fitted lateral type, i.e., a combination of devices rotating and oscillating around a vertical axis, it suflicies to provide a needle-bar guide device which comprises mounting pivotally in an axis parallel to the needle-bar a needle-bar guide which makes oscillating reciprocatory rotations around saidaxis and transfixing to the rocking side of said needle-bar guide a needle-bar whereby said needle-bar is caused to oscillate laterally with respect to the center-line of the stitchmg.

However, as it is necessary not only that the foregoing device be incorporated in the hollow arm together with other mechanisms but also that it be allowed a motional space whose section describes a fan-like shape, the oscillating radius of the aforesaid needle-bar guide of necessity becomes limited and the radius of the locus of oscillations described by the needle point becomes small.

Therefore, as shown in FIG. 3, the locus of oscillations b exhibits an arc of small radius. And inasmuch as the operating locus d of the loop-taker assumes a tangential relationship with respect to the aforesaid locus of oscillations b, when the oscillatory amplitude of the needle becomes large, the needle-drop point becomes more remote from the aforesaid operating locus d. As a result, with the loop-taker rotating without being able to seize the loop of the needle-thread at the needle point, there arises the defectthat the formation of stitch becomes impossible. Hence, in order to remove this defect, there have been used those in which the aforesaid loop-taker is made to move along the locus of oscillations of the aforesaid needle point. However, in these cases it becomes necessary that a complicated oscillatory mechanism be provided for oscillating the aforesaid loop-taker. Moreover, the zigzag stitches produced by these sewing machines were extremely unsatisfactory in appearance.

This invention is able to remove these numerous defects as described hereinabove and thus provide a zigzag sewing machine at low cost. By using the needle-bar guide mechanism of this invention as described hereinbefore, it is possible to lessen the oscillating radius of the needle-bar guide, whereby the space occupied by it in the hollow arm is minimized. In addition, the oscill'atory radius of the needle point can be enlarged sufiiciently. Thus a locus of oscillations b with an arc of large radius, as shown in FIG. 3, is obtainable. Therefore with the needle-drop point being at approximately the same point as the needle-drop point 0' on the aforesaid locus of oscillations b, even if its distance from the center-line of stitching -A becomes great, its distance with respect to the aforesaid operating locus d never becomes pronounced.

Therefore, in accordance with this invention it is possible to obtain not only a sewing machine possessing the functional effectiveness as described hereinbefore, but also since the structure of the sewing machine can be simplified and moreover the oscillatory mechanism for oscillating the needle-bar guide can be made as to be of the lateral type, the assembly of the sewing machine as a whole is simplified and the production cost is thereby lowered.

Since it is apparent that many changes and modifications can be made in the above-described details without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited, to said details except as set forth in the appended claims.

What is claimed:

1. A zigzag sewing machine having a frame comprising a bed, a bracket arm mounted above said bed and having a hollow head at its free terminal portion, a main shaft supported in said bracket art, a needle-bar provided with a needle at its lower end, a needle-bar guide for supporting said needle-bar in said hollow head of said frame, said needle-bar guide being pivotally mounted in said hollow head of said frame, said needle-bar being supported in said needle-bar guideto be slidable in its axial direction, a first connecting means between said a main shaft and said needle-bar for converting the rotation of said main shaft into reciprocating movements of said needle-bar in its axial direction, a needle-bar oscillating mechanism, a second connecting means between said needle-bar guide and said needle-bar oscillating mechanism for oscillating said needle-bar guide around its pivotal axis, a feed-dog for feeding Work in either a forward or rearward direction, a shuttle which in cooperation with said needle-bar moves about a stationary axis for forming the zigzag stitches, said stationary axis being included in a plane substantially perpendicular to said bed and parallel to the line of feed direction of the work held by said feed-dog, and the relative position of the pivotal axis of said needle-bar guide and the axis of said needle-bar being in a non-parallel state, and an extension of the pivotal axis of said needle-bar guide passing outside the extremities of said needle-bar, and also the spread between said axes becoming wider the lower they proceed, whereby said needle-bar makes upand-down reciprocating movements as well as arc-like oscillating movements in a lateral direction.

2. A zigzag sewing machine having a frame comprising a bed, a bracket arm mounted above said bed and having a hollow head at its free terminal portion, a main shaft supported in said bracket arm, a needle-bar provided with a needle at its lower end, a needle-bar guide for supporting said needle-bar in said hollow head of said frame, said needle-bar guide being pivotally mounted in said hollow head of said frame, said needle-bar being supported in said needle-bar guide to be slidable in its axial direction, a first connecting means between said main shaft and said needle-bar for converting the rotation of said main shaft into reciprocating movements of said needle-bar in its axial direction, a needle-bar oscillating mechanism, a second connecting means between said needle-bar guide and said needle-bar oscillating mechanism for oscillating said needle-bar guide around its pivotal axis, a feed-dog for feeding work in either a forward or rearward direction, a shuttle which in cooperation with said needle-bar moves about a stationary axis for forming the zigzag stitches, said stationary axis being included in a plane substantially perpendicular to said bed and parallel to the line of feed direction of the needle-bar that is described on the work is caused to approach a portion of the locus described by the beak of a loop-taker.

References Cited in the file of this patent like locus of oscillations of the extended axis of said 10 2,921,545

UNITED STATES PATENTS Wood Feb. 16, Court Jan. 26, Garasimowicz Feb. 18, Johnson Jan. 19, 

